What drinking does to your body

The annual party season finds many of us indulging to excess. But what are we doing to our bodies? Maxine Frith finds that the health effects of alcohol go far beyond a nasty headache the morning after

A woman's risk of breast cancer rises by six per cent for each extra alcoholic drink she has, on average, every day. Cancer Research UK estimates that alcohol accounts for around four per cent of breast cancers in the developed world. Overall, 5,000 cancer deaths a year are attributed to alcohol, although red wine in moderation is believed by some scientists to help protect against some forms of the disease, such as cancer of the bowel.

DIGESTIVE SYSTEM

It's a familiar sight on any high street at this time of year - the drinker who has had one too many and is disgorging their night's intake.

The chemicals in alcohol can irritate the lining of the stomach, prompting the body to expel them by vomiting. Most alcoholic drinks are high in sugar, calories and carbohydrates, so that you may not want to eat because you feel full, even though your body is not getting any nutrients. The sugar also triggers the production of insulin, which in turn reduces blood sugar levels. This explains those hungover feelings of trembling and hunger the next morning.

In the long term, regular, heavy drinking can lead to peptic ulcers, inflammation of the pancreas and cancer, while alcohol impairs the small intestine's ability to process nutrients and vitamins. Continued disruption of insulin production can lead to diabetes.

REPRODUCTIVE SYSTEM

First there's the "beer goggles" effect - when you end up in bed with someone you wouldn't normally touch with a bargepole because your emotional and behavioural barriers are down.

Reduced inhibitions can lead to unsafe sex, with abortion clinics reporting a rise in appointments in January. On the other hand, drinking depresses the nerve impulses that cause erections and can lead to so-called "brewer's droop". Heavy intake causes a drop in testosterone levels in men, leading to shrinkage of the penis and, in some cases, long-term impotence and problems. Alcohol can also damage sperm and egg production and the ability of a fertilised egg to implant in the womb.

LIVER

Alcohol is absorbed into the blood from the stomach and intestines and passes through the liver before circulating around the body. Thus it is the liver that has to deal with the highest concentrations of damaging chemicals.

As the liver breaks down alcohol, a by-product called acetaldehyde is formed, which is almost as toxic as the original product itself. If large amounts of alcohol are constantly being processed, acetaldehyde can cause scarring of the liver which leads to cirrhosis, damaging its ability to function and restricting the blood flow to cells. A night of heavy drinking can upset the balance of enzymes and disrupt fat metabolism, which over time can build up and engorge the liver. Excess drinking can also cause hepatitis, which can be fatal. Both hepatitis and cirrhosis can cause the skin to become jaundiced, as well as causing anaemia, lower back pain and severe swelling of the abdomen. One in ten heavy drinkers will develop cirrhosis, and a transplant is the only cure.

THE UNBORN CHILD

The accepted wisdom is that a moderate intake of around two units per week during pregnancy will not affect the unborn child.

But scientists now believe that even one glass of wine a week during pregnancy can make the foetus "jump" in the womb and slow its development.

Excessive drinking while pregnant can cause Foetal Alcohol Syndrome, where babies have a low birthweight, reduced intelligence and facial deformities.

BRAIN

Alcohol boosts production the "feel-good" neurotransmitters such as dopamine and serotonin, but when you stop drinking, these levels plummet. Alcohol can also cause brain cells to swell. Permanent disruption of dopamine levels can cause depression and increases the risk of stroke by 42 per cent, according to research. Cognitive functions learned later in life, such as decorum, are the first to be affected by alcohol, and are followed by disruption to the brain cells associated with attention, sleep, co-ordination and memory. If someone drinks until they pass out, the parts of the brain that control breathing are affected. In extreme cases, the brain shuts down and the drinker lapses into a coma. Excessive alcohol intake is the most common cause of sudden fits in young men and up to 50 per cent of weekend A&E department admissions are alcohol related.

MOUTH AND THROAT

Alcohol is the main reason behind a recent steep rise in cases of mouth cancers, the charity Cancer Research warned last week.

Mouth cancer now kills 1,600 people in the UK every year, more than cervical and testicular cancer combined. The chance of surviving for five years with mouth cancer is just 50 per cent.

Doctors believe that three quarters of cases of the disease could be prevented by more moderate consumption of alcohol. Alcohol contains chemicals called nitrosamines that can cause cancer in the mouth, voicebox, pharynx and oesophagus.

LEGS, ARMS AND BONES

Alcohol acts like an anaesthetic in the bloodstream, so that after a drink or three, your limbs become more relaxed and you are less likely to feel pain.

More worryingly, alcohol interferes with the body's ability to absorb calcium, resulting in the softening and weakening of bones that can lead to osteoporosis.

Drinking can also weaken muscles and cause pain and spasms in the arms and legs.

The damage to the body's central nervous system by alcohol can cause permanent tingling or numbness in the fingers and toes.

COMPLEXION

Drinking causes the small blood vessels in the skin to widen, allowing more blood to flow to the surface and causing that flushed, rosy-cheeked look that dominates so many Christmas party photographs.

Alcohol causes temporary disruption to the body's antidiuretic mechanism, which is why there are always long queues outside the toilets of pubs and clubs.

This disruption also means that people who are drinking a lot are likely to sweat more, as their bodies try to absorb the alcohol and adjust to the dehydrating affect it causes.

You may look shiny and full of colour the night before, but the morning after your body will struggle to re-hydrate and draws fluid from the top layers of skin, leaving the surface of your face dry and flaky.

Long term drinking can cause the skin capillaries to break up, leading to a permanently flushed and puffy look with bloodshot eyes.

More seriously, alcohol is linked to the painful skin complaint psoriasis, particularly in men, as well as eczema.

HEART

It's not all bad news of course. Numerous studies have shown that moderate intake of red wine can protect against colds, Alzheimer's and heart disease.

Scientists believe that red wine contains chemicals called polyphenols that interfere with the formation of endothelin-1 - the substance in the body that causes arteries to clog and raises the risk of heart attacks.

However, the latest study on the subject, published in The Lancet last week, rubbished that theory and said that the risks far outweigh the benefits.

Alcohol is a vasodilator, which means it makes the peripheral blood vessels relax in order to allow more blood to flow through to the skin and tissues.

Even one unit quickens your pulse rate, as your heart begins to work harder in order to pump enough blood to your organs.

In the short term, this just makes you breathe slightly faster and contributes to that "high" feeling while you drink.

But in the long term, alcohol weakens the heart muscle and its ability to pump blood through the body.

It causes high blood pressure, thereby increasing the risk of heart attacks and strokes.

Heavy drinking can cause atrial fibrillation - a rapid, irregular heartbeat that is brought about when the heart's chambers contract too quickly.